Clinical success of intrauterine insemination cycles is affected by the sperm preparation time.

OBJECTIVE

To determine the impact of the time interval from the end of sperm preparation (TSP) to intrauterine insemination (IUI) on the outcome.

DESIGN

Prospective multicentre cohort study.

SETTING

Seven French centers (assisted reproduction group in northeastern France, four academic centers, and three clinics).

PATIENT(S): Eight hundred sixty-two IUI cycles (709 patients) managed by gonadotropins were studied.

INTERVENTION(S): Cycles were stimulated by either FSH or hMG, and hCG was administrated when the leading follicle diameter measured >15 mm. IUIs were performed ∼ 36 hours after ovulation triggering.

MAIN OUTCOME MEASURE(S): Generalized linear mixed models for binary outcomes were used to model clinical pregnancy (CP) to assess the effect of TSP adjusted for other predictors (such as maternal age, semen quality, and indication of IUI treatment).

RESULT(S): The TSP effect was significant, featuring an inverse U-shaped curve admitting an optimum interval of ∼ 40-80 minutes improving CP compared with other values. Other significant predictors were total motile spermatozoa inseminated, maternal age, and unexplained infertility.

CONCLUSION(S): The observance of TSP in the range of 40-80 minutes has a potential positive effect on pregnancy rate, while not requiring the investment of supplemental resources. This finding awaits confirmation in randomized trials.